From: Christoph Lameter __clear_bit_unlock does not need to perform atomic operations on the variable. Avoid a cmpxchg and simply do a store with release semantics. Add a barrier to be safe that the compiler does not do funky things. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Christoph Lameter Acked-by: Nick Piggin Cc: "Luck, Tony" Signed-off-by: Andrew Morton --- include/asm-ia64/bitops.h | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff -puN include/asm-ia64/bitops.h~ia64-slim-down-__clear_bit_unlock include/asm-ia64/bitops.h --- a/include/asm-ia64/bitops.h~ia64-slim-down-__clear_bit_unlock +++ a/include/asm-ia64/bitops.h @@ -124,10 +124,21 @@ clear_bit_unlock (int nr, volatile void /** * __clear_bit_unlock - Non-atomically clear a bit with release * - * This is like clear_bit_unlock, but the implementation may use a non-atomic - * store (this one uses an atomic, however). + * This is like clear_bit_unlock, but the implementation uses a store + * with release semantics. See also __raw_spin_unlock(). */ -#define __clear_bit_unlock clear_bit_unlock +static __inline__ void +__clear_bit_unlock(int nr, volatile void *addr) +{ + __u32 mask, new; + volatile __u32 *m; + + m = (volatile __u32 *)addr + (nr >> 5); + mask = ~(1 << (nr & 31)); + new = *m & mask; + barrier(); + asm volatile ("st4.rel.nta [%0] = %1\n\t" :: "r"(m), "r"(new)); +} /** * __clear_bit - Clears a bit in memory (non-atomic version) _